fabrication and applications of nanostructured surfaces ...€¦ · •objective: create and...

Nanostructured sensors

Raphaël Pugin

Section Head Nanoscale Technology

Copyright 2017 CSEM | Raphaël Pugin| Page 1

Why nanostructures?

Adhesion &

wettability

• Superhydrophobicity

• Anti-icing

• Dry-adhesion

• Friction

• Cell-substrates

interactions

Photovoltaics

• Light trapping

structures

1µm

Sensors

• Higher sensitivity

• Faster

responsiveness

• Lower drift

Optics

CSEM’s DID

• Anti-reflective properties

• Structural colours

• Plasmonic


CSEM objective and strategy

• Develop processes and manufacturing chains for the large volume fabrication of

submicro-/nanostructured surfaces, films, components with enhanced

performances or unique properties.

Origination of Micro-/Nano-structures and

Self- Assembly eg. Nanospherelithography

Sol-gel processes

Upscaling or Replication

Dry etchingHot embossing

UV nanoimprintInjection MoldingSlot Die Coating

Surface functionalization

Molecular vapor deposition

(SAMs, metal oxide thin films)

Dye or Enzyme Encapsultation

Characterization & Integration

Performance evaluation

Demo: Nanostructured functional components


Outline

• Manufacturing of plastic nanostructured biodiagnostic platform

• Origination of low-cost, large scale nanostructures

• Upscaling or replication of nanostructures by injection molding

• Demonstration of improved performances (signal homogeneity, sensitivity)

• Manufacturing of disposable patch & film for gas sensing

• Fabrication of functional mesoporous sol-gel film

• Integration for Life Sciences

• Pressure Sensitive Painting for Aeronautics

• Air quality monitoring application

|


Nanostructured biodiagnostic platform

• Objectives:

Improve sensitivity of injection-molding bio-

diagnostic platform with nanostructuration

• Control of the wettability of detection spots

• Improve signal quality and homogeneity

• Tooling: fabrication of nanostructures on a mold

insert presenting microchannels and micropins

• Replication : optimization of the replication

process for nanostructured micromolds


Micro- and nano-structures tested

• Origination of nanostructures by beads and polymer self-

assembly

• Replication into plastic, fabrication of nanostructured

biodiagnostic platform:

• Hot embossing and Injection molding: PC parts with

four different structures

• Characterization:

• Influence of structuring on wettability

• Biodiagnostic platform : fluorescence immunoassay

Hot embossed S0 Hot embossed S1

Hot embossed S2 Hot embossed S3

Injection molded nanoInjection molded micro


Influence of structuring on wettability

• Dynamic contact angles of water measured on the four types of hot embossed

structures and, as a control, flat PC

0

20

40

60

80

100

120

140

160

PC FLAT PC bicontinuous

PC S16 PC S28 PC S29

Wat

er

con

tact

an

gle

[°]

• Advancing water contact angle and contact angle hysteresis significantly

increased

• Wetting mode : Wenzel type (sticky drops)

S0 S1 S2 S3


Tests using a model immunoassay

• In these tests, the antibody used for detection is inkjet-printed on the spots of the

bio-diagnostic platform.

• The fluorescent spots were imaged using a confocal microscope

• Results:

• Better spot homogeneity: no coffee-ring effect after spotting

• 30% increase in fluorescence for structure S3 (increase in specific surface, different

roughness, possible scattering of the emitted light)

Flat S1

S2 S3No

rma

lise

dgain


Manufacturing of functional mesoporous films

• Objective:

Develop disposable sensitive film enabling the

optical detection of dissolved analytes or gases

• Low cost manufacturing process

• Higher performance: shorter response

time, higher sensitivity

• Manufacturing: Optimize and upscale

sol-gel coating

• Highly controlled range of porosity and

chemical composition


Advantages:• Dye chemical protection• Reduction of self-quenching• Larger interface, larger loading

rate, higher emitted intensity• Open structure, negligible impact on

response time• Enhanced sensitivity to O2/CO2

• Lower impact of H2O• Linear sensitivity curves• Enhanced lifetime• No drift

New chemically sensitive optical patches

• State-of-the-art: sensitive molecules embedded into a matrix (polymeric, inorganic)

• Encapsulation of active species into a secondary microporous matrix

Mesoporous

CSEM Patent pending

Hierarchically porous


Demox

• Determine oygen concentration in cell and tissue culture

• Bio-compatible low cost sensor (disposable SG patch)

• Customizable readers equipped with integrated optics and electronics

• CSEM provides complete solution

• Bio-Innovation Prize awarded to CSEM by the Fondation Eclosion


O2 sensor performances

Reference fluorimeter

• Frequency-domain lifetime fluorimetry

• SPECIFICATIONS accuracy and confidence interval (CI)

• Single point calibration in ambient air

• 0-21% O2 (stable environment)

O2 sensing in gas phase at 23/37°C and 70/90% humidity

Accuracy0.1% at 2% O2

0.2% at 21% O2

Precision - 95% confidence interval±0.3% at 2% O2

±0.3% at 21% O2


Sensitive mesoporous layers for aeronautic

• Pressure-Sensitive Paintings (PSP) for aero-dynamic testing in wind tunnel: meso-

porous sol-gel coatings are used to measure fast pressure variations observed in an

unsteady aerodynamic flow

• Higher sensibility when compared to standard PSP, better performances in

luminescence (10x) and responsiveness (Facq. up to 10KHz vs Facq.< 1KHz for std PSP).

• Technology patented, will be transfered to ONERA (2017-18) for commercialization

– CCIFS Innovation Trophy awarded to CSEM


CO2 sensor for air quality monitoring, prototype fabricated

• Highly sensitive CO2 sensing foil based on patent pending fabrication process

• Sensing patch easy to replace

• Miniature optical reader with reflector system needs low power


CO2 sensor performances

• Absorbance

• SPECIFICATIONS accuracy and confidence interval (CI)

• Single point calibration in ambient air

• 0-15% CO2 (stable environment) – phenol red

Reference spectrometer

CO2 sensing in gas phase at 23°C and 70% humidity

Accuracy0.2% at 3% CO2

0.2% at 12% CO2

Precision - 95% confidence interval±0.4% at 3% CO2

±1% at 12% CO2


Conclusions

• Process chains for the fabrication of nanostructures surfaces and components have

been developed and patented:

• nanostructured plastic chip by injection molding

• Mesoporous films by sol-gel process

• Functional nanostructured sensors have been fabricated for different applications

• High performance biodiagnostic platform

• Optical sensor for O2 monitoring in cell culture device

• Pressure sensitive painting for aeronautics

• Optical sensor for CO2 monitoring (Life Sciences and air quality control)

Thank you for your attentionand follow us on

www.csem.ch


Sensor performances

Optical gas sensing

Gas concentration Gas concentration

Gas concentration Gas concentration

calibrated gas

• Accuracy & Precision

3D mold insert structuring


• Objective : deposition of nanoparticles on the mold insert produced by Vuillermoz

(in the holes made by micromilling (Ø300µm, depth 150µm))

• Successfull deposition at the bottom of the microholes

Deposition of particles on the microstructured mold insert


Deposition of particles on the microstructured mold insert

• Deposition on the sidewalls of the microholes

• The background roughness due to the micromilling process does not affect the

deposition process


Deposition of particles on freeform parts

Deposition on

a coronary

stent


3D mold insert structuring

• Use the process developped for 2D parts onto

the 3D mold insert.

• Fabrication of a nanoporous etch mask and

electrochemical etching

• Nanostructures have been fabricated

into the microholes

• Homogeneity to be improved

• Difficulties to characterize the results

(AFM not possible)


Origination of nanopatterns by self-assembly

• Fabrication of a formulation containing micro-nanoparticles or block

copolymers and deposition of thin films on a substrate

Material costs: 20€/100g

Formulation/Dispersion Deposition

Particles or

polymers

+ solvent

+additives

Characterization

Fabrication of nanostructures


Random low-cost nanostructures transfered in replication tool

• Self-Assembled structures transferred in nickel or hard steel replication tools

• 2 and 3D nanostructured inserts and mold



Replication


• Rapid prototyping

• Highest accuracy

• UV-curable resins

(PUA, solgel)

UV Nanoimprint Hot embossing Injection molding

• Small series production

• Thermoplastic &

thermosetting materials

• High throughput

• Large series

production

2µm1µm500nm 1µm

http://www.google.ch/url?sa=i&rct=j&q=billion+200t&source=images&cd=&cad=rja&docid=FzLrBloqmg09EM&tbnid=HsbJnnujJn2LhM:&ved=0CAUQjRw&url=http://www.directindustry.fr/prod/billion/presses-a-injecter-multi-matieres-horizontales-electriques-20395-1000653.html&ei=qLRvUePPF8aVPZqZgdAE&bvm=bv.45368065,d.ZWU&psig=AFQjCNFXFvf7eNxdDG9yxcaWUKOpf9lLTQ&ust=1366361636809547

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Superhydrophobic surfaces

• Fabrication of micro/nanostructured

plastic parts using replication

techniques.

• Control surface chemistry using

MVD™ technology

• Characterization of wettability :

dynamic water contact-angles, high

speed videos recording of drop

impacts

Chemistry: Perfluoro SAM

• Superhydropbobic, self-cleaning surfaces

• Controlled wetting states (Wenzel vs

Cassie-baxter)

• Superhydrophilic /hemiwicking surface

also possible

Applications


Superhydrophobic surfaces

o High speed video records of water drops impacts on superhydrophobic surfaces:

Structure 2Flat Structure 1


Anti-icing surfaces

• Objective:

Fabrication of superhydrophobic surfaces with enhanced

erosion resistance to improve the performance of

electromechanical de-icers and lower their energy

consumption

• Fabrication of nanostructured surfaces by

means of UV-nanoimprint

• Control surface chemistry using MVD™

technology

• Characterization: measurement of ice-adhesion

strength, outdoor icing tests

Lift decreases

Weight increases

Airflow disrupted

Drag increases

Applications

ICEAGE


Anti-icing surfaces

• Both structured/flat samples are iced with

snow gun

• Ice easily removed from nanostructured

samples by pole shaking

• Ice remained on polished Al surface, event

after scratching

• Ice adhesion strength measured by

applying shear until the pellet adhesively or

cohesively breaks

Applications

F

ICEAGE


Application: wearable device

• Objective: Create and integrate PV solution in a wristband

• Fabricate textured surface for the growth of the flexible solar

cell that provide excellent light coupling capabilities

• Outstanding PV performance at ultra-low illumination

• Upscaling of the texturation process (30x30 cm2) successful.

UV-NIL on 30-200µm thick polymer foil

Nano-Surface Engineering


Nanostructured biodiagnostic platform

• Objective :

Injection molding of nanostructured bio-

diagnostic platform with improved sensitivity

• Control of the wettability of detection spots

• Improve signal quality and homogeneity

• Tooling: fabrication of nanostructures on a

mold insert presenting microchannels and

microholes

• Replication : optimization of the

replication process for nanostructured

micromolds

Applications


Biological cell growth

• Grow eukaryotic cells on flat and structured

surfaces

• Analyse the morphology of the cells after 3days

• Characterize the adhesion of cells on

flat/structured surfaces

• Control the growth of adherent cells via

micro-nanostructuring surfaces.

• Create surfaces with cell-adhesion/cell

repellent patterns

Applications


Functionalisation via aerosol-jet printing

• Aerosol-jet printer system AJ-300

• Aerodynamic focusing of colloidal suspension

• Contact-free deposition

• 3D and flexible substrates

• Deposited materials incl. metals, polymers,

ceramics, dielectrics, biomaterials…

2 mm1 mm

Electrode on pipet tip


Biofunctionalisation by Aerosol Jet Printing

• Currently optimising deposition parameters for biological samples on various

chemistries

• Spots can be done on structured or 3D samples

Fluorescent BSA spotted on aminosilaneslide (Nexterion Slide A+, Schott)

Average spot size: 67 μm Average size: 68 μm

Fluorescent BSA spotted on hydrogel slide (Nexterion Slide H, Schott)

Fluorescent BSA spotted on epoxysilaneslide (Nexterion Slide E, Schott)

Average spot size: 79 μm

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